8" Subwoofer Enclosure Part 2 (with thiele-small now)

[hernanstafe]

Ok so i'm finally gonna buy a new sub instead of using my old 8" speakers. It's an 8" Selenium sub. These are the thielle small parameters:

Fs: 40Hz
Re: 3,2 Ohms
Qms: 15,80
Qes: 0,65
Qts: 0,62
Vas: 20 l
Ref Eff: 0,26%
Sd: 0,022 Square Meters
Vd: 77,9 cubic centimiters
Xmax: 3,5mm
BetaL: 8,1 Tm

I'd like to know if someone can tell me the enclosure size and schematics, a ported enclosure if possible (i think they sound better than a closed one?)
Thanks again everyone!

 

[zlast]

sub

If you are going to buy a new driver to make a sub...do the design work BEFOR you purchase...that way you know your driver will be suitable. If you randonly purchase a driver it may not fit into a size box or have the output you desire. Check out this:

http://www.linearteam.org/winisd.html

WINISD is a free program you can use to model subwoofer enclosures. Enter the Small/Thiel parameters of your driver, WINISD will model an "optimal" enclosure based on these parameters. For example, the SELENIUM driver you mention has an optimal vented enclosure of 83 liters vented at 26 Hz. With this program you can model the driver/enclosure BEFOR you buy. 86 liters for an 8 inch sub is rather large. For example, if you used the DAYTON 8 inch:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-545

IN a 23 liter enclusure tuned to 36 HZ, your overall enclosure would be about 1/4th the size. So get WINISD, and you can start selecting a driver that will give you what you want...one last word, WINISD (and any speaker modeling program) is not 100 percent accurate. And it doesnt tell you how the speaker will sound. So asking others who have built a certain speaker their impressions is also important.

 

[Cal Weldon]

Hi Herman,

I am glad you decided against using the old woofer and have started anew.

First off, I am a Selenium fan and have a number of their products. If you are looking at the 8SW8A, that is a car woofer and an entry level one at that. It is not what you would call a sub. It is a small motor lightweight woofer. This will work OK in the car but if you are planning this for the house, you'll want something else.

 

[hernanstafe]

Hey Cal, once again thanks for replying. Well i didn't have much time to look for subs this morning and that Selenium one was the only one i could find, where i live is kind of hard to find good audio products, and if you find them the price is RIDICULOUS. So i'm going to see if i can get something better in the afternoon.

Oh, i sent you an email i don't know if you got it/read it.

 

[Cal Weldon]

Herman,

I don't know what drivers are available in Argentina. It would be nice to buy something that close. Yes those are rather inexpensive and maybe suited for some but if you want it inside, I use a pair of these that do a nice job in a 200ft^3 room.

They are on special now.

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=264-854

 

[hernanstafe]

err that's a nice speaker, but i don't think i can get one of those here!!. I'm still wondering, i want to use the Selenium speaker with a TDA2030 based amp, and to use with a computer (i mean it's not like i'm going to use it at parties or anything), so is that selenium THAT bad? Right now i'm using an Aiwa 4" sub and performs awesome. take a look at this, what i want to build is similar to that.

http://rapidshare.com/files/15132586/Subwoofer.rar.html

 

[Cal Weldon]

Hi Herman,

No that woofer is not that bad at all. I just don't want you thinking it is good and be disappointed.

As a computer speaker it will be just fine.

Far better than any 4".

EDIT: I don't know how to access the pics.

 

[hernanstafe]

alright then, i think i'll use that selenium, i've been trying to find something else but that's all they sell here. I was wondering if you could help me with the box, a 4th bandpass class if possible. I was trying to use winisd but it asks me some parameters of the speaker i don't have. if you could help me out i'd certainly apreciate it.

 

[Cal Weldon]

I'm sorry. I haven't much cared for the bandpass sound so I have never looked at how to design one. Others might be able to help here.

 

[AKN]

Hi hernanstafe,

I was trying to use winisd but it asks me some parameters of the speaker i don't have

What parameters do you miss?

 

[zlast]

subwoofer

The only Small Thiel parameters you REALLY need for WINISD are:

VAS
QMS
QES
QTS
FS

While the other parameters are critical for some things, you probably only need the above to get started...so dont worry if you dont have the BL or SD for a speaker...with the above parameters you can calculate box volume...